QUESTION 1

A manufacturer wants to estimate the mean time that it takes for a specific part to be added to a vehicle during production. A small pilot study showed a mean of 57 minutes with a standard deviation of 7.5 minutes. If they wish to be within 2 minutes of the true mean with 95% confidence, how large a sample should they look at?

QUESTION 2

A city counselor wishes to know what proportion of her constituents would be in favour of installing a splash pad in the local park. If she wishes to be 97% confident that the sample proportion is within 3.5% of the population proportion, how many of her constituents should she sample?Past studies have indicated that 73% are usually in favour.